scholarly journals Larval chaetotaxy and morphometry of Oosternum costatum (Coleoptera: Hydrophilidae) including a discussion of larval characters with phylogenetic relevance

2018 ◽  
Vol 58 (2) ◽  
pp. 499-511 ◽  
Author(s):  
Miguel Archangelsky

Abstract The primary and secondary chaetotaxy of the head capsule and head appendages of the first and third larval instars of Oosternum costatum (LeConte, 1855) (Coleoptera: Hydrophilidae: Sphaeridiinae, Megasternini) are described for the first time. Morphometric characters derived from the head capsule and mouthparts are included, together with detailed illustrations of all characters. The morphology and chaetotaxy of these larvae is compared to that of other larvae of the tribe Megasternini, confirming that chaetotaxy is a useful source of characters for phylogenetic analyses. Comparative notes with Sphaeridium Fabricius, 1775 (Sphaeridiini) are also included.

Zootaxa ◽  
2020 ◽  
Vol 4722 (5) ◽  
pp. 423-442
Author(s):  
GEORGINA RODRIGUEZ ◽  
PATRICIA L. M. TORRES ◽  
MIGUEL ARCHANGELSKY

The primary and secondary chaetotaxy of the head capsule and head appendages of the three larval instars of the water scavenger beetle genus Derallus Sharp are described for the first time based on two species: D. angustus Sharp and D. paranensis Oliva. Morphometric characters derived from the head capsule and mouthparts are included, together with detailed illustrations of all characters. Chaetotaxy of these larvae is compared with that of Regimbartia attenuata (Fabricius), another species belonging to the Derallus-clade of Berosini.


2009 ◽  
Vol 43 (1) ◽  
pp. e-15-e-24
Author(s):  
I. Dolinskaya

Formation of Pattern and Diagnostic Instar Features of the Head in Caterpillars from Genus Peridea (Lepidoptera, Notodontidae) Pattern and colouration of caterpillar head of all larval instar of 7 species from genus Peridea Stephens, 1828 are studied. Formation of caterpillar head pattern in ontogenesis is discussed. Diagnostic characters, both specific and larval instars, are recorded for the first time. Key to species according to larval instars is given. Evidently, only larvae of the 1st instar demonstrate different directions in the pattern formation. This characteristic can be used for clearing of taxonomic relations in the genera and on the earliest ontogenetic stages (1st larval instar) only. In the following (2nd-5th) instars, the pattern became more or less of the same type. It depends on stripes shape or colouration only and can serve as good specific diagnostic character. To determine larval instar, both width of the head capsule and head pattern should be taken into account.


Zootaxa ◽  
2020 ◽  
Vol 4718 (3) ◽  
pp. 436-446
Author(s):  
EDWARD TSYRLIN ◽  
MELISSA CAREW ◽  
YVES ALARIE

The second and third larval instars of the Australian endemic dytiscid Chostonectes nebulosus (Macleay, 1871) are described and illustrated for the first time including a detailed chaetotaxic analysis of head capsule and appendages, legs, last abdominal segment and urogomphi. Collected larvae were successfully associated with adults using rearing and a molecular approach. The identification key and COI barcodes for C. nebulosus, C. gigas (Boheman, 1858) and C. johnsonii (Clark, 1862) are provided. 


Author(s):  
Miguel Archangelsky ◽  
Nicolás Rafael Martínez Román ◽  
Martin Fikáček

Abstract Phylogenetic analyses testing the monophyly of the tribe Hydrobiusini and the relationships among its genera are performed based on a data matrix including characters of larval morphology and morphometrics, larval chaetotaxy and adult morphology, including eight of the nine hydrobiusine genera plus 15 outgroup taxa. The head chaetotaxy of six genera of the tribe Hydrobiusini is described (Ametor, Hybogralius, Hydramara, Limnohydrobius, Limnoxenus and Sperchopsis). Morphometric characters derived from the head capsule and mouthparts are included. All characters are illustrated in detail. The analyses performed on the above datasets and their combinations reveal the monophyly of the Hydrobiusini except for Hybogralius, and reconstruct the internal topology of the tribe, largely corresponding to results of previous molecular analyses. Hybogralius groups with genera having larvae adapted to underwater feeding in all analyses. The position of the genus Tritonus within the Laccobiini is questioned by our analyses, which suggest a closer relationship with the tribes Hydrophilini or Hydrobiusini. Larval characters are revealed as highly homoplastic, with chaetotaxic characters performing slightly worse than usual larval morphology. Nonetheless, they are phylogenetically informative and useful for testing phylogenetic hypotheses resulting from analyses of molecules or adult morphology. A key to larvae of the genera of the Hydrobiusini is presented.


Parasitology ◽  
2011 ◽  
Vol 138 (5) ◽  
pp. 638-647 ◽  
Author(s):  
GABRIELA HRČKOVA ◽  
MARTINA MITERPÁKOVÁ ◽  
ANNE O'CONNOR ◽  
VILIAM ŠNÁBEL ◽  
PETER D. OLSON

SUMMARYHere we examine 3157 foxes from 6 districts of the Slovak Republic in order to determine for the first time the distribution, prevalence and identity ofMesocestodesspp. endemic to this part of central Europe. During the period 2001–2006, an average of 41·9% of foxes were found to harbourMesocestoidesinfections. Among the samples we confirmed the widespread and common occurrence ofM. litteratus(Batsch, 1786), and report the presence, for the first time, ofM. lineatus(Goeze, 1782) in the Slovak Republic, where it has a more restricted geographical range and low prevalence (7%). Using a combination of 12S rDNA, CO1 and ND1 mitochondrial gene sequences together with analysis of 13 morphometric characters, we show that the two species are genetically distinct and can be differentiated by discrete breaks in the ranges of the male and female reproductive characters, but not by the more commonly examined characters of the scolex and strobila. Estimates of interspecific divergence withinMesocestoidesranged from 9 to 18%, whereas intraspecific variation was less than 2%, and phylogenetic analyses of the data showed that despite overlapping geographical ranges, the two commonly reported European species are not closely related, withM. litteratusmore closely allied to North American isolates ofMesocestoidesthan toM. lineatus. We confirm that morphological analysis of reproductive organs can be used to reliably discriminate between these often sympatric species obtained from red foxes.


1965 ◽  
Vol 55 (4) ◽  
pp. 747-759 ◽  
Author(s):  
P. Osborne

Experimental evidence is given to show that only two larval instars occur during the development of Meligethes aeneus (F.) (Coleoptera, Nitidulidae) under laboratory conditions in Scotland, based on the facts that there is only one moult and only one increase in head-capsule width. The egg, first- and second-instar larvae, prepupa and pupa of M. aeneus are described and compared with the corresponding stages of M. viridescens (F.). The larvae of the two species are differentiated for the first time by the arrangement of dorsal cuticular tubercles, the size and form of the urogomphi and the width of the head capsules.


2021 ◽  
Vol 7 (6) ◽  
pp. 478
Author(s):  
Xue-Wei Wang ◽  
Tom W. May ◽  
Shi-Liang Liu ◽  
Li-Wei Zhou

Hyphodontia sensu lato, belonging to Hymenochaetales, accommodates corticioid wood-inhabiting basidiomycetous fungi with resupinate basidiocarps and diverse hymenophoral characters. Species diversity of Hyphodontia sensu lato has been extensively explored worldwide, but in previous studies the six accepted genera in Hyphodontia sensu lato, viz. Fasciodontia, Hastodontia, Hyphodontia, Kneiffiella, Lyomyces and Xylodon were not all strongly supported from a phylogenetic perspective. Moreover, the relationships among these six genera in Hyphodontia sensu lato and other lineages within Hymenochaetales are not clear. In this study, we performed comprehensive phylogenetic analyses on the basis of multiple loci. For the first time, the independence of each of the six genera receives strong phylogenetic support. The six genera are separated in four clades within Hymenochaetales: Fasciodontia, Lyomyces and Xylodon are accepted as members of a previously known family Schizoporaceae, Kneiffiella and Hyphodontia are, respectively, placed in two monotypic families, viz. a previous name Chaetoporellaceae and a newly introduced name Hyphodontiaceae, and Hastodontia is considered to be a genus with an uncertain taxonomic position at the family rank within Hymenochaetales. The three families emerged between 61.51 and 195.87 million years ago. Compared to other families in the Hymenochaetales, these ages are more or less similar to those of Coltriciaceae, Hymenochaetaceae and Oxyporaceae, but much older than those of the two families Neoantrodiellaceae and Nigrofomitaceae. In regard to species, two, one, three and 10 species are newly described from Hyphodontia, Kneiffiella, Lyomyces and Xylodon, respectively. The taxonomic status of additional 30 species names from these four genera is briefly discussed; an epitype is designated for X. australis. The resupinate habit and poroid hymenophoral configuration were evaluated as the ancestral state of basidiocarps within Hymenochaetales. The resupinate habit mainly remains, while the hymenophoral configuration mainly evolves to the grandinioid-odontioid state and also back to the poroid state at the family level. Generally, a taxonomic framework for Hymenochaetales with an emphasis on members belonging to Hyphodontia sensu lato is constructed, and trait evolution of basidiocarps within Hymenochaetales is revealed accordingly.


Zootaxa ◽  
2017 ◽  
Vol 4238 (4) ◽  
pp. 451 ◽  
Author(s):  
ALBERT DELER-HERNÁNDEZ ◽  
JUAN A. DELGADO

Preimaginal stages of the six species of Hydraenidae presently known from Cuba were obtained by rearing adults in the laboratory. Eggs of Hydraena perkinsi Spangler, 1980, H. decui Spangler, 1980 and H. franklyni Deler-Hernández & Delgado, 2012 are described and illustrated for the first time. The first instar larva of Gymnochthebius fossatus (LeConte, 1855) is redescribed, adding some new remarkable morphological characters including what could be the first abdominal egg-burster reported for this family. All larval instars of H. perkinsi, H. guadelupensis Orchymont, 1923 and Ochthebius attritus LeConte, 1878 are described and illustrated for the first time, with a special emphasis on their chaetotaxy. The second instar larva of G. fossatus along with first and third instar larvae of H. decui and H. franklyni are also studied for the first time. The pupal morphology and vestiture of a species belonging to the genus Hydraena are described for the first time, based on the pupa of H. perkinsi. Biological notes for several preimaginal stages of the studied species are also given. 


Author(s):  
Alec R. Lackmann ◽  
Malcolm G. Butler

Except for one unconfirmed case, chironomid larvae have been reported to pass through four larval instars between egg and pupal stages. We have observed a fifth larval instar to be a standard life-cycle feature of the podonomine Trichotanypus alaskensis Brundin 1966 in tundra ponds on the Arctic Coastal Plain near Barrow, Alaska. T. alaskensis has a one-year life cycle in these arctic ponds. Adults emerge in June ~2-3 weeks after pond thaw, then mate and oviposit; most newly-hatched larvae reach instar IV by October when pond sediments freeze. Overwintering larvae complete instar IV within a few days of thaw, then molt again to a fifth larval instar. Imaginal discs, normally seen only during instar IV in Chironomidae, develop across both instars IV & V prior to pupation and adult emergence. While monitoring larval development post-thaw in 2014, we noticed freshly-molted T. alaskensis larval exuviae a week or more prior to any pupation by that species. In 2015-16 we reared overwintering instar IV larvae from single pond sources, individually with daily monitoring, through molts to instar V, pupa, and adult. Some overwintering instar II and III larvae were reared as well, but were few in number. During 2016 we also reared T. alaskensis progeny (from eggs) through instar II, thus documenting head capsule size ranges for all five instars in a single pond’s population. Without individual rearings, the fifth larval instar was not readily apparent for two reasons: 1) The molt itself occurs immediately after thaw and is so synchronous it is difficult to discern in daily field samples. 2) The head capsule size increment between instars IV-V is much lower than the ratio predicted by the Brooks-Dyar Rule. Up through instar IV, the Brooks-Dyar ratio for T. alaskensis ranged 1.30-1.61, but during the IV-V molt head capsule dimensions (sexes pooled) increased by a ratio of 1.09 – comparable to the magnitude of sexual dimorphism in head capsule size within each of the final two larval instars. Individual rearings coupled with 2014-2016 field surveys in nine other ponds suggest that five larval instars is an obligatory trait of this species at this location. As this is the first confirmed case of five larval instars in a chironomid, the phylogenetic uniqueness of this trait needs further investigation.


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